1. Field of the Invention
The present invention generally relates to a tape cassette and more particularly is directed to a tape cassette suitable in the use of recording and reproducing a digital signal, for example, a PCM (pulse code modulated) signal.
2. Description of the Prior Art
In an ordinary tape cassette such as a standard type tape cassette now widely used in which no lid is provided at its front opening portion, the tape cassette is provided with a tape-end sensing mechanism for sensing the end of tape winding or tape rewinding.
In such tape end sensing mechanisms, it is proposed to electrically sense a small piece of aluminum foil which is attached to, for example, the tape beginning or end, or to optically sense a transparent leader tape which is bonded to the tape beginning or end, etc.
The conventional tape-end sensing means or mechanism to detect the tape beginning or end can easily be provided in such prior systems because the above tape cassette casing has no lid provided at its front opening portion.
However, in a tape cassette in which an analog signal is converted to a PCM signal and then recorded on a tape and in which when it is loaded onto a PCM signal recording and reproducing apparatus, the tape is usually extracted out of the tape cassette, such tape cassette is required to have a lid to prevent fingerprints, dust, or the like from adhering to the tape stretched over the front opening portion of the cassette casing upon non-use. As a result, it is quite difficult to incorporate the tape-end sensing means of the non-lidded tape cassette to one having the lid at its front opening portion. However, it is desired that the above lidded tape cassette be provided with tape-end sensing means.